One vertex per element, one color per generator, with an edge from x to x·s.
(2,4)(6,8)(9,10)(11,15)(12,16)(13,14)(17,23)(18,21)(19,24)(20,22)(25,26,30,33)(27,34,28,31)(29,37,38,32)(35,39,36,40)(10,14)(15,21)(16,22)(23,24)(25,26)(27,34)(28,31)(29,32)(30,33)(35,40)(36,39)(37,38) involution — undirected(1,2,5,4)(3,6,7,8)(25,27,30,28)(26,31,33,34)(29,35,38,36)(32,39,37,40)(3,7)(6,8)(9,10)(11,15)(12,16)(13,14)(17,23)(18,21)(19,24)(20,22)(25,26)(27,31)(28,34)(29,32)(30,33)(35,39)(36,40)(37,38) involution — undirected(1,3,5,7)(2,6,4,8)(9,11,13,18)(10,15,14,21)(12,19,20,17)(16,24,22,23)(25,28,30,27)(26,31,33,34)(29,36,38,35)(32,39,37,40)(1,4,5,2)(3,8,7,6)(9,12,13,20)(10,16,14,22)(11,17,18,19)(15,23,21,24)(25,29)(26,32)(27,35)(28,36)(30,38)(31,39)(33,37)(34,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.